The prevalence of subscribers to cellular phone networks has reached 90% or more of the entire population in developed countries. In some of the developed countries, the prevalence of the subscribers has reached nearly 120%. Thus, the spread of cellular phones to general users has already reached saturation. Meanwhile, in order for a cellular phone operator to further improve sales, it is necessary to increase the number of subscribers to cellular phones. Therefore, the Machine-to-Machine (M2M) market in which communication is performed not between persons but between machines has been attracting attention as a new target for subscribers to cellular phones. Possible examples of a machine terminal include a vending machine, an automobile (car navigation), and a traffic light.
Patent Literature 1 discloses the following configuration as an example using the machine terminal. A computer located in an office or the like acquires inventory data on warehouses, vending machines, and the like located at remote locations, via a network using a cellular phone. Thus, the acquisition of the inventory data via the network using the cellular phone eliminates the need for a dedicated line between each vending machine or the like and the office, and reduces a construction cost for laying the dedicated line, for example.
When the communication between machine terminals is compared with the communication between user terminals such as cellular phones, there is the following difference. That is, there is a large difference between “quality level required for communication service” which is required for the network in the communication between machine terminals and “quality level required for communication service” which is required for the network in the communication between user terminals. Specifically, in voice call, web browsing, and the like performed by a general user, the general user can notice a disconnection of the communication or a delay in the communication. Thus, the disconnection of the communication or the delay in the communication makes the user notice uncomfortable. Therefore, there is a demand for an extremely high quality level of communication service.
On the other hand, the main operation in the communication performed by machine terminals is uploading or downloading of data on a regular basis (once a day, one every several hours, etc.). Accordingly, communication service provided using machine terminals is less affected by a disconnection of the communication, a delay in the communication, or the like. As a result, when the communication between user terminals is compared with the communication between machine terminals, the “quality level required for communication service” which is required for the communication between machine terminals is relatively low.
Therefore, if the number of subscribers to machine terminals is increased to the same level as the number of subscribers of general users in the future, an expansion of networks for general users as networks for processing traffic of machine terminals may result in excessive capital investment.